One means of analyzing signals is, for example, to observe the spectrum. The measuring devices used for this purpose must, on the one hand, provide the widest possible bandwidth so that signal components with different frequencies can be registered securely and, on the other hand, the signal component registered must be compared continuously with a threshold value, so that a trigger pulse can be output whenever the threshold value set is either overshot or undershot. For example, with EMC measurements (electromagnetic compatibility), it is desirable to register even very short interferers. To achieve this goal, the signal is sampled with the fastest possible sampling rate. The sampled and digitized signal must then be further processed with an extremely fast computer in order to extract the required information.
A frequency-mask trigger unit which allows a triggering with signals under analysis which are transformed into the frequency domain is known from EP 2 219 039 A2, whereas the amplitude of these signals can fluctuate strongly. The disadvantage with EP 2 219 039 A2 is that short interferers within the signal under analysis can only be detected with difficulty using the frequency-mask trigger unit presented.
What is needed, therefore, is a frequency-mask trigger approach that provides a solution for detecting short interference pulses occurring in the time domain as securely as possible.